1. Field of the Invention
The present invention relates to a semiconductor device inspection apparatus and more particularly to a module appearance inspection apparatus.
2. Description of the Related Art
Semiconductor devices are often used in a module which includes a printed circuit board and semiconductor devices attached on the printed circuit board. For example, a memory module includes memory integrated circuits on a printed circuit board on which circuit patterns electrically connect the memory integrated circuits to interface terminals on the printed circuit board. The interface terminals are often called xe2x80x98tabsxe2x80x99, and electrically connect the memory module to an external component.
Typically, after assembly, the memory modules undergo a series of electrical tests and an appearance inspection. The electrical tests determine whether the module meets the requirements for electrical operations, and the appearance inspection determines whether the module has any physical defects such as warping of the module.
The module appearance inspection is done manually by visual inspection. Accordingly, the appearance inspection is subject to human errors, low inspection accuracy, and long inspection time.
The present invention is directed to an apparatus for inspecting the appearance of semiconductor device modules, such as single-inline-memory-modules (SIMMs) and dual-inline-memory-modules (DIMMs). The apparatus includes a warpage checking unit, a visual checking unit, a first module transfer unit for unloading modules from a module tray, a second module transfer unit for transferring modules within the apparatus, and a third module transfer unit for loading modules to another module tray.
Each of the first module transfer unit and the third module transfer unit inicludes a module pickup unit that grips the module and a module pickup moving unit that moves the module pickup unit in X-Y directions. The module pickup unit includes: a vertical cylinder for moving the module pickup unit up and down; a fixed frame; a rotating frame coupled to the fixed frame such that the rotating frame can rotate against the fixed frame; and a module gripper connecting to the rotating frame to bold the module. The module gripper includes: a guide rail; the driving pulley rotated by a space control motor; a passive pulley driven by the driving pulley through a belt which is wound around the driving pulley and the passive pulley; a pair of guide blocks moving along the guide rail and coupled to the belt; and a pair of gripping parts respectively coupled to the guide blocks. The gripping parts move close to each other or away from each other depending on the direction of rotation of the driving pulley so that the gripping parts grip or release the module.
The second module transfer unit includes a module inverting unit and a moving unit for moving the module inverting unit in the X-Y directions. The module inverting unit includes: a first motor driving a vertical shaft of the module inverting unit such that the module inverting unit moves up and down; a second motor that rotates and drives back and forth a horizontal shaft of the module inverting unit; and a module gripping member coupled to the horizontal shaft such that the module gripping member rotates with the horizontal shaft.
The warpage checking unit includes sensors spaced apart from one another and a sensor moving unit for adjusting the distances between the sensors. The sensor moving unit includes: a warpage checking unit body having a slot; a driving pulley rotated by a space control motor; a passive pulley driven by the driving pulley through a belt which is wound around the driving pulley and the passive pulley; and guide blocks moving along the slot and coupled to the belt, wherein the sensors are respectively coupled to the guide blocks. The sensors move close to each other or away from each other depending on the direction of rotation of the driving pulley, so that the sensors can adjust to modules various sizes.
The apparatus can replace the first and third module transfer units with a single module transfer unit. In this case, the apparatus includes: a warpage checking unit; a visual checking unit; a supply unit in which module trays are stacked; a storage unit in which module trays also can be stacked; a tray transfer unit which moves a module tray from the supply unit to the storage unit; a first module transfer unit which unloads and loads the modules from and to the module trays on the tray transfer unit; and a second module transfer unit which transfers the module from the warpage checking unit or the visual checking unit.
Each of the supply unit and the storage unit includes a module tray releasing/receiving unit having a module tray supporting device. The module tray supporting device lifts the module trays to isolate a module tray from the stacked module trays of the supply unit, or for insertion of a module tray into a bottom of the stack in the storage unit. The module tray supporting device includes: a vertical shaft moving up and down when driven by a first cylinder; a module tray supporting rod coupled to the vertical shaft; and a second cylinder driving the module tray supporting rod back and forth, so that the module tray supporting rod moves under or retracts from the stacked module trays.